TRENTON — U.S. Attorney General Eric Holder introduced a sweeping shift in the country’s decades-long war on drugs today, aiming to curb severe prison overcrowding by scaling back mandatory minimum sentences for low-level drug offenders.

Experts said the plan mirrored efforts made by a number of states in recent years — including a New Jersey bill signed and supported by Gov. Chris Christie last year that sends nonviolent drug offenders to rehabilitation centers instead of serving jail time.

"We must face the reality that as it stands, our system is, in too many ways, broken," he said in a speech at the American Bar Association’s annual meeting in San Francisco.

Holder said he wanted to divert those convicted of low-level crimes to drug treatment and community service programs and to expand a program to allow for the release of some elderly, non-violent offenders.

"With an outsized, unnecessarily large prison population, we need to ensure that incarceration is used to punish, to deter and to rehabilitate — not merely to warehouse and to forget," he said.

Federal prisons are currently operating at nearly 40 percent above capacity, holding more than 219,000 inmates, and almost half are serving time for drug-related crimes.

Holder’s plan does not extend to crimes prosecuted at the state and local level. State prisons hold about 1.4 million inmates, with about 225 serving time on drug offenses, according to figures from the U.S. Bureau of Justice Statistics.

Still, Adam Gelb, director of the Public Safety Performance Project the Pew Charitable Trusts, said, "There is a sea change under way in how our country deals with issues of crime and punishment."

"We are moving away from the notion that locking up as many people for as long as possible is the best way to fight crime," Gelb said.

Laura W. Murphy, director of the Washington office of the American Civil Liberties Union, said the group was "thrilled by these long-awaited developments."

"These policies will make it more likely that wasteful and harmful federal prison overcrowding will end," Murphy said.

Mandatory minimum prison sentences, a product of the federal government’s war on drugs that began in the 1980s, limit the discretion of judges to impose shorter prison sentences.

Holder said mandatory minimums have helped cause the number of inmates in federal prisons to jump 800 percent since 1980 and cost the U.S. $80 billion in 2010 alone.

The attorney general said that under the new policy, defendants will be charged with offenses for which accompanying sentences "are better suited to their individual conduct, rather than excessive prison terms more appropriate for violent criminals or drug kingpins."

In July, Christie signed a bill that expands eligibility for New Jersey’s drug court program and mandates that nonviolent drug offenders receive treatment instead of prison time. The legislation phases in a statewide program over five years, starting with three counties in the first year.

Christie’s office declined to comment on Holder’s speech, referring to comments the governor made in his State of the State address last January. "It will send a clear message to those who have fallen victim to the disease of drug abuse — we want to help you, not throw you away," Christie said.

State Sen. Raymond Lesniak (D-Union), who sponsored the bill, said today he was "excited" by Holder’s remarks, emphasizing that throwing low-level drug users in prison is a problem.

"Not only is it wasting lives, it’s wasting money," Lesniak said. "And it’s not providing safety to the public. Statistics show that people with substance addictions who commit crimes and get treatment, the chances of them committing a crime again are much, much lower than someone just going to prison."

State Sen. Joseph Vitale (D-Middlesex) noted that drugs are often only one issue that offenders are tackling and treatment programs can help them cope better than prison.

"We have to treat a variety of things that go on with the offender," Vitale said.

The unanswered question is how each of the U.S. Attorneys offices around the country will implement changes, given the authority of prosecutors to exercise discretion in how they handle their criminal cases.

African-Americans and Hispanics would probably benefit the most from a change, since together they account for about 70 percent of federal drug convictions each year, according to Marc Mauer, executive director of the Sentencing Project, a nonprofit group involved in research and policy reform of the criminal justice system.

If state policymakers were to adopt similar policies, the effect of changes at the state level could be even broader, Mauer said.

Holder said mandatory minimum sentences "breed disrespect for the system."

"When applied indiscriminately, they do not serve public safety," he said. "They have had a disabling effect on communities. And they are ultimately counterproductive."

Holder said new approaches — which he is calling the "Smart On Crime" initiative — are the result of a Justice Department review he launched early this year.

But support for the plan was not universal. U.S. Rep. Bob Goodlatte (R-Va.), chairman of the House Judiciary Committee, said Holder "cannot unilaterally ignore the laws or the limits on his executive powers."

"While the attorney general has the ability to use prosecutorial discretion in individual cases, that authority does not extend to entire categories of people," Goodlatte said.

U.S. Sen. Chuck Grassley of Iowa, the top Republican on the Senate Judiciary Committee, said that whether the law needs to be changed should be decided by the Congress, along with the president.

"The overreach by the administration to unilaterally decide which laws to enforce and which laws to ignore is a disturbing trend," Grasskey said.

Star-Ledger staff writer Christopher Baxter and the Associated Press contributed to this report.